The study developed a module in Grammar and Composition II and looked into its eﬀects on the achievement of first year students of the College of Arts and Sciences. Quasi-experimental design specifically the non-equivalent control group design was used in this study. The respondents were selected from the two classes in English 11- Grammar and Composition II. Twenty were selected and paired through their pretest scores. One class was taken as the experimental group in which the modular approach was used, while the other class made up the control group in which the lecture method was employed. Two instruments were used to collect data. The first was a 60 –item multiple-choice test and a ten-point essay. The other instrument was a 20-item questionnaire. Frequency counts, percentages, means, and variance were used to describe the gathered data. A t-test for correlated samples was used to determine whether there were significant diﬀerences in the pretest and posttest scores of the control and experimental groups. The study indicated that there was a significant diﬀerence between the posttest scores of the students exposed to the module compared with the ones exposed to the lecture method. This shows that students taught via module in Grammar and Composition II performed better than those who did not. Based on the findings of the study, it is concluded that the proposed module is eﬀective in improving students’ achievement in English Grammar and Composition II.